Hi,
Thank you for posting your query on Microsoft Community.
As per the description, I understand that you are unable to use camera app.
Try the Methods.
Method 1:
I would also suggest you to run the Hardware and devices troubleshooter to troubleshoot the device:
a. Press Windows key to launch the Start screen.
b. Type “Troubleshooting” without quotes and click on Troubleshooting.
c. In the new window, click View all on the left pane.
d. In the list of options, click on Hardware and devices.
e. Click Next and follow the on-screen instructions.
Method 2:
If you have not followed the troubleshooting steps, you may refer to the section “Why doesn't my webcam work with the Camera app or other apps?” in the following article and try to install the updates and the drivers:
Camera app and webcams: FAQ
http://windows.microsoft.com/en-IN/windows-8/camera-app-faq
Method 3:
Try to install the older version driver for the camera in compatibility mode:
a. Right click on setup file.
b. Click on Properties.
c. Click on Compatibility tab.
d. Put a check mark on Run this program in compatibility mode for.
e. Select the operating system to which the driver is available.
f. Put a check mark on Run this program as an administrator under Privilege Level.
Hope this information helps. Please let us know if you need any other assistance with Windows in future. We will be happy to assist you.